Mom, you were my age once, you grew up at a different time, you had different friends etc. I need to figure this out by myself. I love you more than anything else in this world but I need to find my own way. Will you give me some freedom to do that? i promise you it will come to pass and we will end up laughing at this in the near future.
It's commendable that you want to have that conversation with her without being disrespectful!!! I wish more teens were like that. I'd pretty much just bring it up much like you worded it here :-)
You may want whatever you want for yourself. It isn't disrespectful for you to want to dess yourself. Its actually disrespectful for her to expect you to constantly submit to being dressed by her. The way you said it above is really great. I'd actually almost say it word for word back to her actually. Gl!